[Xen-changelog] [xen master] x86/pvh: do not allow 32-bit PVH guests to clear CR4's PAE bit

[patchbot@xxxxxxx]

commit 476cf36ac0de41bd5070f902c430d5ce90c7f590
Author:     Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
AuthorDate: Wed Sep 9 17:08:56 2015 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Sep 9 17:08:56 2015 +0200

    x86/pvh: do not allow 32-bit PVH guests to clear CR4's PAE bit
    
    .. since we only support 32-bit PV(H) guests in PAE mode.
    
    Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/hvm/hvm.c |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index a38c302..c6d2e59 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3522,11 +3522,19 @@ int hvm_set_cr4(unsigned long value, bool_t may_defer)
         goto gpf;
     }
 
-    if ( !(value & X86_CR4_PAE) && hvm_long_mode_enabled(v) )
+    if ( !(value & X86_CR4_PAE) )
     {
-        HVM_DBG_LOG(DBG_LEVEL_1, "Guest cleared CR4.PAE while "
-                    "EFER.LMA is set");
-        goto gpf;
+        if ( hvm_long_mode_enabled(v) )
+        {
+            HVM_DBG_LOG(DBG_LEVEL_1, "Guest cleared CR4.PAE while "
+                        "EFER.LMA is set");
+            goto gpf;
+        }
+        if ( is_pvh_vcpu(v) )
+        {
+            HVM_DBG_LOG(DBG_LEVEL_1, "32-bit PVH guest cleared CR4.PAE");
+            goto gpf;
+        }
     }
 
     old_cr = v->arch.hvm_vcpu.guest_cr[4];
--
generated by git-patchbot for /home/xen/git/xen.git#master

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